Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
  • H04L9/32—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols including means for verifying the identity or authority of a user of the system or for message authentication, e.g. authorization, entity authentication, data integrity or data verification, non-repudiation, key authentication or verification of credentials
  • H04L9/3236—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols including means for verifying the identity or authority of a user of the system or for message authentication, e.g. authorization, entity authentication, data integrity or data verification, non-repudiation, key authentication or verification of credentials using cryptographic hash functions
  • H04L9/3242—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols including means for verifying the identity or authority of a user of the system or for message authentication, e.g. authorization, entity authentication, data integrity or data verification, non-repudiation, key authentication or verification of credentials using cryptographic hash functions involving keyed hash functions, e.g. message authentication codes [MACs], CBC-MAC or HMAC
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
  • H04L9/06—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols the encryption apparatus using shift registers or memories for block-wise or stream coding, e.g. DES systems or RC4; Hash functions; Pseudorandom sequence generators
  • H04L9/0618—Block ciphers, i.e. encrypting groups of characters of a plain text message using fixed encryption transformation
  • H04L9/0637—Modes of operation, e.g. cipher block chaining [CBC], electronic codebook [ECB] or Galois/counter mode [GCM]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
  • H04L9/50—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols using hash chains, e.g. blockchains or hash trees
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L2209/00—Additional information or applications relating to cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
  • H04L2209/12—Details relating to cryptographic hardware or logic circuitry
  • H04L2209/125—Parallelization or pipelining, e.g. for accelerating processing of cryptographic operations

Definitions

• a so-called message authentication code was usually determined as proof of the integrity.
• any hash method or also methods according to the ISO 9797 standard can be used to form a MAC.
• block encryption methods were used for the transmission of data blocks.
• chaining mode in the context of block encryption for stream-oriented encryption, for example the so-called cipher block chaining mode (CBC mode).
• an encryption mode that is block-oriented for the transmission of data blocks would be required, which has the property of accidental or willful disturbances of the encrypted data stream during the transmission between a sender and a receiver to cause a strong error propagation of the decrypted data stream at the recipient.
• the known chaining modes often have weak error propagation due to the so-called self-synchronization, for example the CBC mode.
• the well-known chaining modes with strong error propagation also contain cryptographic weaknesses, so that they are implicitly used in an encryption process for the mutual guarantee of integrity and confidentiality, ie. H. in one process step are unsuitable.
• CBC message authentication code contains only a limited and fixed number of information bits. This ensures the security of an identity check value used
• the invention is therefore based on the problem of specifying an arrangement and a method for the cryptographic processing of a digital data stream, with which or with which both the security service of confidentiality and the security service of integrity are possible with a reduced need for computing capacity.
• a first processing element is provided for at least some of the data blocks of the data stream to be transmitted, which processing element contains at least a first link unit, an encryption unit and a second link unit.
• the data of the respective data block is fed to the first linking unit via a first input
• the data of a previous data block is fed via the second input
• a previous intermediate variable is fed via a third input.
• These sizes become a link size in the link unit connected .
• the link size is supplied to the link unit in which a block encryption method is applied to the link size.
• the result of the block encryption is an intermediate variable which is fed to the second linking unit.
• a previous cryptographically processed data block is fed to the second linking unit.
• the cryptographically processed data block for the respective data block is determined.
• the entirety of the cryptographically processed data blocks results in the digital data stream to be transmitted.
• a second processing element is provided for at least a part of cryptographically processed data blocks, which has at least a third link unit, a decryption unit and a fourth link unit.
• the third linking unit is supplied with the received cryptographically processed data block via a first input and at least one previous cryptographically processed data block via a second input.
• the data blocks are linked together in the third link unit.
• the result of the link in the third link unit is the intermediate size.
• the intermediate size is decrypted with the decryption unit and a link size is determined.
• the fourth linking unit is supplied with the link size via a second input, at least one previous intermediate size and via a third input, at least one previous data block, and linked in the fourth linking unit to form the data block.
• a transmitting unit and a receiving unit are provided, which are each designed according to the arrangement according to claim 1 and according to the arrangement according to claim 2. Furthermore, an over- Carrying system between the transmitting unit and the receiving unit provided for the transmission of the cryptographically processed data stream.
• the arrangements have u. a. the advantage that for the first time encryption and integrity protection in one processing step, encryption becomes possible. An additional, explicit integrity assurance is no longer required with this arrangement. This leads to a considerable processing speed that can be doubled during the cryptographic processing of a data stream.
• the arrangements have the advantage that a chaining mode is implemented which is clearly superior to the known chaining modes, since on the one hand it has a strong propagation of errors and on the other hand those attacks which cannot be recognized with the PCBC mode can be detected can be.
• Ensuring the implicit integrity by using a constant integrity check value (CICV) and encrypting the data with a highly error-propagating chaining mode allows an advantageous scaling of the security by using arbitrarily long ICVs.
• CICV constant integrity check value
• an intermediate size is determined from a data block by encrypting the data block using a block encryption method, taking into account at least one previous data block and at least one previous intermediate size. Furthermore, the intermediate size is cryptographically processed by linking to at least one preceding one Data block determines a cryptographically processed data block.
• the method according to claim 9 essentially has the inverse steps to the method according to claim 8.
• an intermediate size is determined from the cryptographically processed data block by linking to a previous cryptographically processed data block
• a link size is determined from the intermediate size by a block encryption method by decrypting the intermediate size.
• the link size is linked to at least one previous intermediate size and to at least one previous data block, whereby a data block is determined.
• the method steps according to the method according to claim 8 and the method according to claim 9 are linked to one another in such a way that the cryptographically processed data are first formed in a transmitting unit, are transmitted from the transmitting unit to a receiving unit, and then the cryptographically processed data are processed again according to the method according to claim 9.
• the security of the chaining mode can be advantageously increased compared to other known chaining modes by using a second initialization value as an additional secret parameter in the first processing stage.
• Both the arrangements and the methods can advantageously be used both for encryption alone, for integrity protection alone and for common encryption and integrity protection.
• Figure 1 is a sketch of the arrangement according to claim 1;
• Figure 2 is a sketch of an arrangement according to claim 2;
• 3 is a sketch of the arrangement according to claim 3.
• the digital data stream has any number of data blocks P n .
• the data blocks P n each have any number of bits.
• An index n uniquely designates each data block of the digital data stream and is a natural number between 1 and 1, 1 being a number of data blocks P n .
• a first processing element Bin is provided for at least some of the data blocks P n , the structure of which is explained in more detail below.
• a first linking unit VK1, an encryption unit E ⁇ and a second linking unit VK2 are provided in the first processing element Bin.
• the first logic unit VKl has three inputs.
• the data block P n is fed to the first linking unit VK1 via a first input E1VK1 of the first encryption unit.
• a previous block of data P n is at least _ ⁇ the first linking unit vkl supplied to a second input of the first combination unit E2VK1 vkl.
• the first combination unit VKl is supplied with at least one previous intermediate variable I n _ ⁇ .
• E2VK1 or the third input E3VK1 of the first linking unit VKl is supplied with the directly preceding data packet P n _ ⁇ or the directly preceding intermediate variable I n _ ⁇ , however it is provided in alternative configurations of the arrangement that data packets P n which are further back _2. ••• Pl and more recent intermediate quantities I n _2 •• ⁇ Ii to the first linking unit VKl.
• the first linking unit VK1 is coupled to an encryption unit E ⁇ .
• a link size V n which is determined by linking sizes supplied to the first link unit VK1, is encrypted in the encryption unit E ⁇ .
• the encryption takes place using any so-called block encryption method, for example according to the DES method or also according to the IDEA method. Further block encryption methods can be used without restriction within the framework of these arrangements and within the framework of the methods.
• the secret cryptographic key used for encryption and for the decryption described below is designated by k.
• the encryption unit E - delivers a size I n that corresponds to the encrypted link size V n .
• the intermediate variable I n becomes, on the one hand, a second linking unit VK2 described below and the first link unit VKl of the following first processing element Bln + l supplied.
• the intermediate variable I n is fed to the second logic unit VK2 via a first input E1VK2 of the second logic unit VK2.
• the second logic unit VK2 has a second input E2VK2, via which at least one previous cryptographically processed data block C n _ 1 ( C n _2-... C j _) is fed to the second logic unit VK2.
• the at least one previous cryptographically processed data block C n _! and the intermediate variable I n linked to one another and the linking result forms the cryptographically processed data block C n .
• the first linking unit VK1 and / or the second linking unit VK2 can be designed in a further development of the arrangement in such a way that the supplied data are linked by a bit-wise EXCLUSIVE-OR link.
• first processing element B1 of a different structure for processing the first data block P- ⁇ .
• the first processing element B1 in turn contains the first linking unit VK1, the encryption unit E ⁇ and the second linking unit VK2.
• the first data block P -] _ is fed to the first linking unit VK1 via a first input E1VK1 of the first linking unit VK1. Furthermore, however, a freely definable, advantageously secret first value IV1 is supplied to the first logic unit VK1 in the configuration. In a further development, it is provided that a freely definable second value is fed to the first logic unit VK1 via a third input E3VK1.
• the first processing element Bin differs from the above-described construction of this first processing element Bll for processing the first data packet P-j _ in a further development of the fact that the second Verknüpfungs- unit VK2 not at least one preceding cryptographically phisch processed data block C n - ⁇ is supplied, but via the second input E2VK2 the first value IV1 of the second logic unit VK2.
• the method for processing the digital data stream and for determining the cryptographically processed data blocks C n essentially corresponds to the structure of the arrangement described above.
• At least some of the data blocks P n are encrypted to the intermediate size I n using a block encryption method. At least one previous data block P n _ ⁇ and at least one previous intermediate variable I n _ ⁇ are taken into account in the encryption.
• the intermediate variable I n is linked to a previous cryptographically processed data block n - ⁇ , whereby a cryptographically processed data block C n is formed.
• the data block P n , the previous data block P n _ ⁇ and the previous intermediate size I n _ ⁇ are linked to form a link size V n to which the block encryption method is applied.
• At least one of the two links described above is designed as an EXCLUSIVE-OR link. It is also provided in a further development to link the first data block P- ⁇ with the first value IV1 and in a further embodiment with the second value IV2. It is also provided that the first intermediate variable 1 ⁇ formed is only linked with the first value IV1 to form the first cryptographically processed data block C ] _.
• the arrangement is supplied with cryptographically processed data blocks C n .
• a second processing element B2n is provided, which contains at least a third link unit VK3, a decryption unit D ⁇ and a fourth link unit VK4.
• the third linking unit VK3 has a first input E1VK3, via which at least one preceding cryptographically processed data block C n _ ⁇ is fed to the third linking unit VK3.
• a second input of the third logic unit E2VK3 VK3 is provided, the third through the at least one preceding cryptographically processed data block n _ ⁇ d he logic unit is supplied to VK3.
• the third linking unit VK3 the cryptographically processed data block C n and the at least one previous cryptographically processed data block C n - are linked to form the first intermediate variable I n .
• the intermediate variable I n is supplied to the decryption unit ⁇ -, for example by coupling the third linking unit VK3 to the decryption unit Dj ⁇ .
• the decryption unit D ⁇ is designed such that the intermediate variable I n is decrypted using a cryptographic method using the cryptographic key k.
• the result of the decryption is the link size V n .
• the link quantity V n is fed to the fourth link unit VK4 via a first input E1VK4 of the fourth link unit VK4.
• a second input E2VK4 of the fourth logic unit is provided, via which the fourth logic unit VK4 is supplied with at least one previous intermediate variable I n- 1 ' I n-2- ••• ⁇ 2> ⁇ l.
• a third input of the fourth combining unit E3VK4 VK4 provided at least one previous data block P n _l, ... Pi P2 is supplied via the combination unit of the fourth VK4.
• the configurations of the above-described arrangement described above are also provided for this arrangement, for example the configuration of the linking units VK3, VK4 as EXCLUSIVE-OR linking units.
• the supply of the first value IV1 via the second input E2VK3 to the third logic unit VK3 for processing the first cryptographically processed data block C ] _ is also provided. This also applies to the supply of the first value IV1 via the second input E2VK4 of the fourth logic unit VK4 to the fourth logic unit
• VK4 as well as for the supply of the second value IV2 via the third input E3VK4 of the fourth logic unit VK4.
• the method is designed essentially the same.
• the cryptographically processed data block C n is preceded by at least one linked cryptographically processed data block C n _ ⁇ to the intermediate size I n .
• the intermediate variable I n is decrypted in the decryption unit O - and forms the link variable V n .
• the link variable V n is linked to at least one previous intermediate value I n - ⁇ , .... 12 I ⁇ and at least one previous data block P n _, ..., P 2 , P ⁇ .
• the result of the linkage is then the data block P n again in plain text.
• a transmission system US is provided, with which the encrypted data stream, which is formed from the cryptographically processed data blocks C n , is transmitted from the transmitter unit S to the receiver unit E.
• Any transmission system US can be provided for the transmission of digital data, or for example after conversion into analog data in a transmission system US for the transmission of analog data (cf. FIG. 3).
• a method is also designed in which the method steps described above of the method for forming the cryptographically processed data blocks C n are carried out without change compared to the methods described above.
• the cryptographically processed data blocks C n and possibly other data that form the digital data stream are transmitted from the transmitter unit S to the receiver unit E.
• the method for forming the data blocks P n in plain text, which have been described above, is, as described above, also carried out in the receiver unit E without any change to the received cryptographically processed data blocks C n .
• all of the developments described above are provided without restrictions.
• the value 0 is assigned to the second value IV2.
• Both the arrangement and the methods can advantageously be used either only for encryption, only to ensure the integrity of the data to be transmitted, or also to ensure both security services, confidentiality and integrity.
• this concatenation mode has a strong error propagation, with which it becomes possible to have only one constant CICV integrity value to ensure the integrity of a digital data stream.
• the constant integrity check value CICV can, for example, simply be appended to the end of the digital data stream in a data block and processed equivalent to the digital data stream. If a transmission error occurs or an attempt is made to falsify the digital data stream in any way, this is recognized during decryption by the property of the strong error propagation and the special type of connection of the individual elements of the digital data stream.
• At least the pairwise swapping of the cryptographically processed data blocks C n during the transmission of the digital data stream is recognized in the receiver unit E when the method is carried out or when the arrangement is used. Furthermore, these arrangements or these methods are secure against the so-called "known-plaintext attacks", provided that it is still impossible for an attacker to know the data blocks P n and the cryptographically processed data blocks C n , " the key K and the Determine values IVl and IV2 with an exhaustive key search.

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• Engineering & Computer Science (AREA)
• Computer Security & Cryptography (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Power Engineering (AREA)
• Storage Device Security (AREA)
• Signal Processing For Digital Recording And Reproducing (AREA)

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• 1997
  • 1997-07-02 US US09/242,796 patent/US6542607B1/en not_active Expired - Fee Related
  • 1997-07-02 EP EP97935421A patent/EP0923826B1/fr not_active Expired - Lifetime
  • 1997-07-02 JP JP10512093A patent/JP2000517497A/ja active Pending
  • 1997-07-02 DE DE59708572T patent/DE59708572D1/de not_active Expired - Fee Related
  • 1997-07-02 AT AT97935421T patent/ATE226772T1/de not_active IP Right Cessation
  • 1997-07-02 WO PCT/DE1997/001397 patent/WO1998010559A1/fr active IP Right Grant

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